Applied with a paint roller, the toilet tissue absorbs the oil from freshly laid tar as it dries, keeping it from sticking to shoes or tires. And the biodegradable paper breaks down and disappears in a matter of days.

The process prompted irritated posts from residents on the city’s Facebook page this week, like this one from Madison Lucas: “This is UGLY!! All over Littleton!!” Or from Stephanie Gregory : “My kids and I thought it was vandalism.”

“We use it so we can keep moving and get more done,” said Clay Engelman, a district supervisor in the city’s street and traffic operations division.

He said the tar sets in about 40 minutes but that with the paper in place as a protective and absorbent cover, traffic can hit the street right away.

Littleton started using the toilet paper method last month, and it learned from the mistakes of other cities, including Lincoln, Nebraska.

For instance: Don’t use two-ply bath tissue. The upper ply doesn’t absorb the oil and ends up blowing into people’s yards.

Amy Ford, a spokeswoman for the Colorado Department of Transportation, said she hadn’t heard of the practice being used in the state before. But the agency actually includes TP in its list of materials for sealant application. According to the 2014 CDOT Hot Mix Asphalt Crack Sealing and Filling Best Practices Guidelines, a material may be needed to “reduce or minimize tracking of the sealant by vehicle tires. Common blotting materials include toilet paper, talcum powder, limestone dust, sand, or proprietary, spray-applied detackifiers.”

Kelli Narde, a spokeswoman for Littleton, said the city had been pitched a number of expensive blotting products but that toilet paper came out on top.

“Even though it looks like a Halloween prank, it works and it’s very inexpensive,” she said.

According to the federal charges, Russian operatives spread pro-Trump and anti-Clinton propaganda. They posed as Americans to coordinate and infiltrate political activities. They organized grass roots rallies. They paid for a cage large enough to hold an actress impersonating Clinton in a prison uniform.